Squirting gun and dosing device therefor

ABSTRACT

A squirting gun serving for administration of medicinal and other liquids to animals is provided with an intake system for the liquid to be administered, the same being drawn in through the hollow rod of a discharging piston, and with a dosing device which comprises a stop ring, on, and/or engaging the piston rod, and a stopping disk, at the inner sidewall of the casing of the gun, whereby the movement of the piston in one of its two directions is arrested when the stop rings contact the stopping disk.

United States Patent Halter I [451 Aug. 8, 1972 1 SQUIRTING GUN AND DOSING FOREIGN PATENTS 0R APPLICATIONS DEVICE THEREFOR 14,463 7/1928 Australia 128/223 [72] Inventor: Paul Halter, 43, Tl'ierwilerstrasse, 11,655 3/1933 Australia ..128/223 4103 Bo'nmingen, Switzerland 524,916 8/ 1940 Great Britain ..l28/223 [22] Filed: 1969 Primary Examiner-Joseph S. Reich [21] AWL 862,741 Attomey-Karl F. Jorda and Frederick H. Rabin [57] ABSTRACT il. .......l28/223, l28/23X1ld23235 A Squirting gun serving for administration of I: I /00 medicinal and other liquids to animals is provided with [58] new of Search "128/223, 2371 230 an intake system for the liquid to be administered, the 7 same being drawn in through the hollow rod of a [56] References Cited discharging piston, and with a dosing device which comprises a stop ring, on, and/or engaging the piston UNITED STATES PATENTS rod, and a stopping disk, at the inner sidewall of the 1,982,993 12/1934 Kauzal .128/223 casing the whereby the mwemem 2 074 401 3/1937 Kauzal' [23 4 X piston in one of its two directions is arrestedwhen the 217501943 6/1956 Dann..::::::::::....128/235 smppmg 3,400,716 9/1968 Schultz ..l28/235 X 20 Claim, 15 Drawing Figures -"-19 ;a"v:ti\l\ I 5 k 30 3 11' 9,? 13 i2?? I"! lj\\u\ i I 1!, A -1' x 19 23 a? 1 1 anxxaim'v v v 4 22 9 5 4 a I I v I 1 7 I -v g 20 f 4 ,1 26. 1 1' 1 I 1 1 1' t ,l 31

Patented Aug. 8, 1972 3,682,175

8 Sheets-Sheet 1 FIG.1

PAUL HALTER,

INVENTOR:

5%MMZ Attorneys 8 Sheet-Shee 2 Attorneys Patented Aug. 8, 1972 I"'I' w g y/U I l. i" 3 i E fl I Patented Aug. 8, 1972 8 Sheets-Sheet 6 A PAUL HALTER,

INVENTOR:

Attorneys Patented Aug. 8, 1972 e Sheets-Sheet PAUL HALTER, INVENTOR: BY/% fl a Attorneys Patented Aug. 8, 1972 3,682,175

8 Sheets-Shee 6 PAUL HALTER INVENTOR:

BYI M10. 4!

Attorneys Putented Aug. 8, 1972 8 Sheets-Shee 6 a N. 9 E R PAUL HALTER,

v INVENTORI m/yMla. M

Attorneys Pmmd Aug. 8, 1912 3,682,175

8 Sheets-Sheet 7 PAUL HAL TER INVENTOR:

BY: 4414 a! Attorneys Patented Aug. 8, 1 972 B SheetS-Sheet 8 FIG.1O

PAUL HALTER,

INVENTORZ Jul/( 41a),

SQUIRTING GUN AND DOSING DEVICE THEREFOR The invention concerns a squirting gun which serves in particular for the oral or rectal administration of dosages of a liquid, eg of a medicinal solution or suspension, or, in the rearing of animals, for the administration of dosedquantities of liquids containing fortifying concentrates, vitamins and other similar agents in the form of solutions, suspensions or pastes. The invention also concerns a novel dosage-regulating device for such guns.

Drenching guns are already known which have a relatively complicated construction and wherein adjustment' of any dosing means provided is very troublesome for the use of such drenching guns by untrained personnel in the field, e.g. in a pasture. However, when a certain medicament or other product is to be administered on one or several days to many dozen or even several hundred head of cattle by one or several persons, and the dose must be varied according to the kind or size of animal, the construction of the gun and the setting of the dosage should be as simple as possible. Such a gun should also require as few repairs as possible, since repair shops are often few in number and/or a great distance away.

The object of the invention is, therefore, to provide a gun having the aforesaid advantages. This object is achieved by the gun according to the invention, which serves for the administration of liquid in fixed dosages, in particular for veterinary purposes and is provided with a device for regulating the dosage by means of the stroke of a piston, mounted on a piston rod, which draws the liquid into a chamber in the gun casing and then discharges it again, by way of a mouthpiece having an outlet valve, the gun being further provided with a trigger lever, the discharging movement of the piston being effected by actuating the trigger lever by hand, and wherein the intake return movement of the piston is accomplished by a spring means acting on the trigger lever, its energy being transferred from the trigger lever Furthermore, the dosing device according to the invention comprises, besides the said stopping disk, a setting knob which indicates the position of the stopping disk. This knob is preferably mounted on the outside of the gun casing wall and is detachably connected with the stopping disk through an opening in the casing wall and this setting knob, when rotated, carries the stopping disk along with it. By detaching the knob from the stopping disk, thesev parts of the dosing device, or the stopping disk alone, can be replaced.

The control knob or another appropriate adjusting means forthe dosage-setting device is located preferably on the right or left side at the side wall of the gun casing and at such a level above the trigger lever of the gun that it can be operated, if .desired, with one finger of the same hand in which the gun is being held by the person operating it. The other hand may be free to hold the animal being treated.

A special construction of the cam disk, provides several abutting surfaces on the edge thereof and allows two, threeor more notches for the control knob of the dosing device. This permits arapid operation of the device by the operator.

The method of adjusting the desired dosage is especially advantageous because it can be performed by a simple manipulation, while the gun is introduced orally or rectally to one animal to be treated after another in to the piston via a bi-furcated upper end of the trigger lever and via the piston rod engaged thereby; a charac- 1 teristic feature of the gun being that the piston rod is hollow and that a check valve which closes with the forward stroke of the piston is provided on the face end of the piston on said piston rod; thus, an amount of liquid to be discharged subsequently in one or several ejections is drawn through the interior of the piston rod and the check valve into the said chamber.

A further feature of the invention resides in that the movement of the piston is limited in one of its two directions of motion by the impact of an abutting means, which is part of the dosing device and is joined to the piston rod, against a stopping means which can be adjusted to the desired stroke volume and is also a part of said dosing device.

In a preferred embodiment the stopping means, which is adjustable to the desired stroke volume, and by means of which the stroke of the piston can be limited either to a desired intake or a desired discharge volume, is devised as a stopping disk serving as arresting member and being adjustable by rotation. Advantageously, this stopping means is a cam disk, which is preferably mounted on a lateral inner wallof the gun casing approximately at a level with the piston rod in a zone near the rear end-position of the abutting means.

rapid succession. Animals which are to be treated with this gun are primarily small mammals such as pigs, sheep, goats, vicunas, but also calves. Valves for the chamber to be charged with liquid are preferably rubber slot valves, which function in any random position.

This construction according to the invention is distinguished by extraordinary simplicity both in the design of all the individual parts as well as their assembly and interchangeability. The individual parts can be made of metal; preferably they are of plastic material.

A main advantage of the gun according to the invention resides in the especially simple and easily interchangeable arrangement of its dosage-setting device.

In contrast to the known guns, in which the dosing device is set by adjusting a screw spindle or the like, the dosing device according to the invention can be actuated by turning the above-described setting knob to the appropriate angle for the desired volume of liquid to be administered. By this rotation, the position of the stopping means, e.g. the above-mentioned cam disk, is so changed that a projection on the trigger lever resting thereon or abutting, it is pressed backwards away from the. discharge opening by the action of the said spring means. Thus the piston forming the terminal wall of the gun chamber is filled with the desired amount of liquid and through coupling the trigger lever is arrested. The volume of the liquid drawn to the device and expelled in usage is controlled.

The invention is illustrated in the drawings by several non-limitative embodiments thereof.

. FIG. 1 shows a first embodiment of a gun according to the invention in a side view from the right;

FIG. 2 shows the same gun after removal of the righthand wall of the casing and the trigger lever, the interior parts being shown partly in side view, and partly in longitudinal section;

mentof the gun according to the invention, showing, however, two of the various positions of thetrigger lever different from that shown in FIG. 2;

FIGS. 6 (a), (b) and (c) are schematic plan views and illustrate various constructions of the cam disk belong- 17 opens. In this way, during the backward stroke of the piston 13, liquid is drawn through'a conduit hose 18 or the like from a storage chamber (not shown) which empties into the piston tube 11 hose being sealingly fitted into the externally ribbed end 19 of the latter in known manner, the liquid being drawn through the ing to the dosing device in the embodiment shown in the preceding figures;

F IG. 7 shows in side view another, preferred embodiment ofthe gun according to the invention, as well asa preferred embodiment of the dosing device therefor;

in the intake end-position; a discharge position being indicated by phantom lines;

' FIGS. 9 (a), (b) and (c) are fragmentary views showing the same section as FIG. 8, but with piston, piston rodand dosing device in three other discharge endpos'itions; the piston and piston rod as well as a few other parts are shown unsectioned;

FIG. is a fragmentary view and shows a longitudinal section in the plane X X vertical to the plane of FIG. 9a through the rear upper part of the gun casing, the piston rod and a contact ring being shown unsectioned; and I FIG. 11 is a fragmentary view and shows a cross section of FIG. 9a along the-plane XI XI, looking into the back end of the gun casing.

More in particular, the gun, according to the invenn -tion shown in the drawings consists of the casing 1 and grip handle 2, preferably integral with each other, produced e.g. from east synthetic resin. The discharge tube 4, in particular in the embodiment shown in FIGS.

1' to 5, is inserted in the front opening 3 of the casing by means of its frusto-conically shaped connecting piece 5, and detachably joined with the casing by a slide lock constituted by the recess 6 in the casing wall 7 and the pin 8 on the outer wall of the cylinder 9 of the connecting piece 5 extending into the casing wall 1.

As can be seen especially in FIG. 2, in the rear end of the casing l opposite to the opening 3, an opening 10 is provided, through which passes a reciprocatingly movable tubular piston rod 11 which includes a slide 7 bearing at its front end flange. 12, on which the piston 13 and piston packing 14 are mounted in such a manner that they can hermetically sealingly slide in the cylinder 9 provided in the connecting piece 5.

The chamber 15 formed in the interior of the cylinder 9 and closed off at the back by the piston 13 can be emptied by way. of -a check valve 16 built into the connecting piece 5 where it merges into discharge tube 4. The chamber is filled with liquid byway of a check valve 17 builtinto the'ope'n end of the piston rod bearing of the piston 13.

These valves are so positionedso that-upon forward motion of the piston 13 towards the discharge tube 4, the valve 16 opens and the valve 17 is closed, while by the backward motion of the piston '13 away from the discharge tube 4, the valve 16 is closed while the valve "no. a shows a longitudinal section of the embodiment shown in FIG. 7 with the piston and trigger lever opened valve '17 into the thus evacuated chamber 15;

while, during the forward stroke of the piston 13, with piston 13 is effected by pulling the trigger lever 20 which is mounted in the grip handle 2 on a pivot 22- detachably fastened in the grip handle wall e.g. bya holding screw 21. In FIGS. 1 and 2, due to the pressure of the flat spring 26, the trigger lever 20 which extends with its upper'part urges the two bi-furcated arms 23, 24 into the casing 1. In FIG. 2, the lever 20 is in the rear end-position, in which the arm 23 rests with a nose 37 (FIG; 2) against the cam disk 25 set at the smallest radius a. The direction of the pressure of the flat spring is indicated by the arrow designated by F in F IG. 3.

The arms 23, 24' of the trigger lever 20 grip the recesses 27, 28 between each of the two pairs of Iongitudinal ridges 29, 30 and 29', 30, respectively, mounted on opposite sides of the outer wall of the piston tube- 11. As shown in FIG. 2, the arms and canning disc and arrest thev piston tube 11 in this manner, and together with it, the piston 13, in the backward end position inside the cylinder 9 of the connecting piece 5. In this position, shown in FIG. 2, the chamber 15 contains the largest volume of liquid that it can hold.

If the trigger lever 20 is then pulled back by hand into the interior of the grip handle 2, the spring 26 is stressed and the upper part of the trigger lever, rotating around the pivot 22, moves forward with its arms 23, 24 and thus pushes against the longitudinal ridges 30, 30 of piston tube 11 and moves piston 13 within the cylinder 9 towards the front end position X (FIG. 5), which is reached when the rear edge 31 of the trigger lever hits the inner wall of the grip handle 2.

In this manner the content of the chamber 15 is emptied through the valve 16 and the mouthpiece of discharge tube 4.

In FIG. 5, there are shown the trigger lever, piston rod and piston, firstly in an intermediate position M with the chamber half filled, and, secondly, in phantom lines, in the empty position A. If, e.g. only a half dose is to be administered instead of a full charge, then'the triggerlever 20 must be stopped in its backward move-i ment, under the influence of the spring 26, in the intermediate position M shown in FIG. 5. This is accomplished by accordinglyadjusting the dosing control device 32 consisting of the cam disk 25, of the-setting knob 34'catching on e.g. a four-edged recess 33, and of the releasable unitI36. Notches 35 facilitate the adjustment of thesetting knob 34 to correspond tofixed preferred doses. I

The-dosingdevice is rotated by meansof the knob 34, for instance, so as to apply the smallest dose until the cam disk 25, fastened eccentrically on the knob, is

pointed with its largest radius b (FIGS. 3 and 5) toward the piston. In this manner the nose 37 of the trigger lever arm 23 abuts against the edge of the cam disk 25 in the above-mentioned intermediate position M. By setting the cam disk 25 at any'position between its largest and smallest radius, c, the trigger lever arm 23 and thus also the piston 13 can be stopped at any intermediate position desired, which may correspond to a desired volume of liquid between the half and the total volume of the cylinder chamber.

An especially exact, secure setting of two, three or more fixed volumes, without fine intermediary adjustment, is easily attained e.g. by correspondingly providing flat segments on the outer edge of the cam disk, as is shown in FIGS. 6 (b) and (c).

In FIG. 6(a), the cam disk has no flat segments. It is therefore possible to attain any volume desired between the largest capacity, obtained by setting the smallest radius a of the cam disk, and the smallest capacity, obtained by setting the largest radius b of the cam disk.

On the other hand, in FIG. 6 (b), a preferred embodiment of the cam disk 25 is shown, in which the edge thereof has two flat segments 40 and 41 corresponding to the shortest radius a and the longest radius b, against which the contact nose 37 of the trigger arm 23 can rest securely in its position. A variation of the dosage due to slight rotation of the cam disk 25 is thus avoided, even without the use of notches 35. FIG. 6 shows a similar cam disk 25 on which, besides the two flatedged segments 40 and 41 for the radii a and b, a third one, 42, is provided for a position having an intermediary radius c lying between a and b. In the same manner, more settings of the dosing device can be provided, but it is recommended for the sake of simple operation to be content with two, three or four.

A particularly preferred embodiment of the cam disk serving as stopping means is shown in the FIGS. 7 to l 1.

In this embodiment the discharge tube 4 is joined by means of a coupling nut 106 with a frustoconical insert 109, preferably made of a transparent material, e.g. a transparent plastic resin such as Plexiglas, which bears an outside screw thread on the connecting portion 104 of the discharge tube 4.

As can be seen in FIGS. 8 to 11, the stopping disk 125 is of circular shape and is provided with a central hollow shaft 133 on the surface of the disk facing the casing wall. The stopping disk is firmly joined, by means of a holding screw 126 extending through shaft 133, with the setting knob 134, which is mounted on the outer wall of the casing, so that setting knob and stopping disk are held together and thus rotate in unison on the outside and the inside, respectively of the casing wall. By means of notches 135 or the like, the

setting knob is held in a random number of positions. The setting knob can be caught in the notches 135, e. g. by means of a small ball 147 and spring 148 provided in a recess 146 of the setting knob. In the embodiment shown in FIGS. 7 to 11, as can be seen from FIG. 7, four different notches are provided which correspond to four different discharge volumes, which are denoted on the setting knob 134 as 5", l0, l5 and The discharge of the dose desired is effected as follows: On the side of the stopping disk 125 facing the piston rod 11 there is an arresting strip 143 eccentrically mounted along a chord of the circular disk sur- Like parts of this and the first described embodiment are designated by the same reference numerals. They have the same functions in both embodiments.

In this preferred embodiment, the grip handle 102 which is preferably integral with the casing 1, is open towards the rear end of the casing; the trigger lever 120 is mounted therein rotatably on the pivot 122. The flat spring 126 presses the trigger lever 120 into the rearward end-position in casing 1, shown in full outline in FIG. 8. In this position the bifurcated arms 123, 124 extending from the upper end of the trigger lever, one of each engaging respectively, between the two longitudinal ridges 129, 130 and 129', 130' of the piston rod 11, hold the piston 13 in its farthest rearward position in the cylinder chamber 15. In this position, a stop ring 137 rigidly mounted-on the piston rod 11, or being integral therewith, in the form'of a flange, is not contacting the stopping disk 125 serving as stopping means. This stop ring 137 has a flat edge on the side facing the stopping disk 125, said flat edge having a recess 139 away from the axis of rotation of the stopping disk 125.

face. The arresting strip 143 is spaced far enough from the axis of the stopping disk and projects far enough out of the circular surface of the stopping disk 125 facing the stop ring 137 so as to contact the opposite flat surface of the stop ring 137, when the arresting strip is in a position below and parallel to the longitudinal axis of the piston rod 1 1, as shown in FIG. 10, whereas, when the setting knob 134 and the stopping disk 125 are rotated 180 so that the arresting strip 143 is in the position indicated in FIG. 11 by 143a, above and parallel to the piston rod axis, the stop ring 137 will not abut against, but bypass the arresting strip 143 during forward movement, as will be explained in detail hereinafter.

The setting indicator 144 (FIG. 7) on the outer casing wall of the gun, shows which discharge volume has been set. If this is the position 25 corresponding to the maximum discharge volume, the stopping disk 125 is in the position shown in FIG. 9c, which is a section along the line IX'. IX of FIG. 11. The arresting strip 143, which is then in the position indicated in FIG. 11 by 143a, has allowed the stop ring 137, thanks to its recess 139, to pass during the forward movement of the piston rod caused by pressing the trigger lever 120 into the grip handle 102 by hand and due to the pressure of the fork arms 123, 124 on the longitudinal ridges 130, the forward movement of the piston rod is finally stopped by the fork arm 123 abutting against the end of the arresting strip 143.

If the setting knob 134 is rotated so that the indicator 144 in FIG. 7 registers with position 5, the stopping disk is in the position shown in FIGS. 90, 10 and 11. The arresting strip 143 is below and parallel to the longitudinal axis of the piston rod, i.e. the position shown by 143 in FIG. 11. In this manner the stop ring 137 contacts the other end, opposite that for position 25, of the arresting strip 143 at the flat edge 138, and the forward movement of the piston rod is stopped after a very short discharge stroke.

If the setting knob 134 is rotated by another 90 so that the indicator 144 in FIG. 7 registers with position 10, the arresting strip 143 is in the position l43b indicated in FIG. 8 by phantom lines, and the forward the piston rod 11, when the trigger lever 120 is pressed into the grip handle 102, is stopped by abutment of the side surface of thestop ring 137, next to the flat edge 138 thereof, against one of the side surfaces of the arresting strip 143.

On the side opposite the stopping means, there is provided in the casing wall an opening 45 through which the screw 36, or 136, respectively, can be.

removed, e.g. by means of ascrew driver, so that the stopping means and the setting knob can be separated from 'one another and be replaced.

What is claimed is:

1. A' squirting gun comprising a device for regulating a dosage .of a liquid to be administered by said gun, a gun casing having a wall providing a cylinder chamber therein, a piston rod, a piston fixed thereon and adapted for reciprocating movement in said cylinder chamber upon a slide bearing at one end thereof, a discharge means having an outlet therein, a trigger lever engaging said piston rod and having a bifurcated end, and spring means for urging said trigger lever, piston rod and piston into one of the end positions of said piston in said chamber, the improvement comprising means providing'a tubular channel in said piston chamber at the end of the rod bearing said piston, and an intake check valve mounted in the latter opening means of said piston rod, whereby an amount of liquid to be discharged can be drawn into said chamber through said channel of said piston rod and said intake check valve during rearward movement of said piston.

2. The improvement as described in claim 1, further comprising abutting means on said piston rod and stopping means connected to the wall of said casing, said abutting means and stopping means being so disposed relative to each other in said casing that the movement of the piston in one of its two directions is arrested by said abutting means abutting against said stopping means.

3. The improvement described in claim 2, wherein said'stopping means for the movementof said piston.

comprise a stopping disk serving as an arresting member.

4. The improvement described in claim 3, wherein the said stopping meansis mounted on a lateral inner wall portion of the gun casing approximately at a level with the said piston rod in a 'zone away from a rearmost position of said piston.

' rodand having means providing an opening into said a projection mounted on said stoppingdisk along a chord thereof, and said stop ring is provided with a recess whereby the forward discharge stroke of the piston is limited, depending upon the position of said stopping disk and arresting member thereon, either by the impact of said stop ring, or of one end of said 7 trigger lever against said trigger lever against said projection.

8. A dosing device for use ina squirting gun comprising a piston mounted on a reciprocable piston rod, which piston during its intake strokeis adapted for drawing liquid to be squirted from said gun in predetermined doses into a chamber provided therefor in-a casing of said gun, said gun further having discharge means including a mouthpiece with an outlet check valvetherein, a trigger lever for effecting the discharging movement of the piston and spring means for ef: fecting the movement of said piston, by action transmitted via said trigger lever to said piston rod, which dosing device comprises adjustable stopping means and abutting means mounted on said piston rod for movement therewith, said stopping means being mounted on an inner, lateral wall of said gun casing approximately I at a level with said piston rod in a zone adjacent an end position of said abutting means.

9. A dosing device as described in claim 8, wherein said stopping means comprise a stopping disk serving as arresting member. 7

10. A dosing device described in claim 9, wherein said dosing device further comprises a setting knob which indicates the position of the stopping disk and which is mounted on an outside wall portion of the gun and detachably joined with said stopping disk so as to turn said disk in unison therewith, when rotated.

11. A dosing device as described in claim 8, wherein said stopping means comprise a circular stopping disk 5, The improvement as described in claim 3, wherein said dosing device comprises, besides the said stopping and arresting strip projecting out of the circular face of said disk toward the piston rod along a chord on said disk.

12. A dosing device as described in claim 8, wherein said abutting means comprises a stop ring rigidly mounted on said piston rod, and extending far enough in the direction of said stopping means so as to abut against the latter when the piston rod moves in one of the stroke-limiting positions of said stopping means.

13. A dosing device as described in claim 1 1, wherein said abutting means comprise a stop ring rigidly mounted on said piston rod in one of plural angular positions, said ring being provided with a marginal recess and said ring extending in the direction of said stopping disk so that said ring contacts said arresting strip in only one of said angular positions thereof.

14. A dosing device as described in claim 13 wherein said abutting means further comprises a fork arm connected to an end of said trigger lever whereby said arm movably employs said piston rod and movably engages said stopping disk, said arresting strip being movable so that alignment of the marginal recess in said stop ring with said arresting strip permits movement of the stop ring past the arresting strip with motion of the piston rod limited by impact of said fork arm resting strip.

15. The improvement described in claim 2, wherein said stopping means comprise a stopping disk bearing an arresting member. v

16. A dosing device as described in claim 8, wherein said stopping means comprise a stopping disk bearing an arresting member.

l7. Dosage-regulating device for use in a pistol for the administration of liquid in determined doses, comprising a pistol casing having an external setting knob thereon and means providing a chamber therewithin; a reciprocable piston adapted to draw in and expel said liquid doses from said chamber, said piston being mounted on a hollow piston rod having stopping means mounted thereon and which projects from an end of said casing and is connected rearwardly outside said casing to a liquid supply line; a discharge tube connected with a valve and mouthpiece; and a trigger lever, whereby the expelling stroke of the piston is effected by manual operation of the said trigger lever; while the intake stroke .of the piston is effected by means of a spring member acting upon the trigger lever and via the said lever upon the piston rod connected to the latter and upon the piston; said device comprising means which limit the stroke of the piston to a length corresponding to a determined liquid volume of said chamber means, said stroke-limiting means being located rearward of said chamber and being adapted to engage at least one'of said stop means connected to said piston rod, said stroke-limiting means comprising a stopping disk angularly adjustable solely by turning of against the arsaid external setting knob provided, said stopping disk being arranged at the inner sidewall of said pistol casing at about the level of the piston rod in the region between the wall of the pistol casing enclosing the piston-rod and an end of the chamber.

18. A dosing device as described in claim 17 wherein said stopping means comprise a circular stopping disk and an arresting strip projecting out of the circular face of said disk toward the piston rod along a chord on said disk.

19. Dosage-regulating device as described in claim 18, wherein said stroke-limiting means comprise a stop ring rigidly mounted on said piston rod and extending far enough in the direction of said stopping disk so as to abut against the arresting strip, but not against the disk itself, thereby limiting reciprocable movement of said piston rod in one direction of motion when said arresting strip is in one of two possible stroke-limiting reciprocable positions parallel to the axis of said piston 20 rod 20. Dosage-regulating device as described in claim 19, wherein said stroke-limiting means further comprise an arm provided at the upper end of trigger lever which is movably connected with the piston rod, and wherein said stop ring is provided with a marginal recess, whereby, when said arresting strip is in one of two possible positions parallel to the axis of the piston rod, the stop ring can move past the arresting strip and the stroke of piston is limited by said arm abutting against said arresting strip. 

1. A squirting gun comprising a device for regulating a dosage of a liquid to be administered by said gun, a gun casing having a wall providing a cylinder chamber therein, a piston rod, a piston fixed thereon and adapted for reciprocating movement in said cylinder chamber upon a slide bearing at one end thereof, a discharge means having an outlet therein, a trigger lever engaging said piston rod and having a bifurcated end, and spring means for urging said trigger lever, piston rod and piston into one of the end positions of said piston in said chamber, the improvement comprising means providing a tubular channel in said piston rod and having means providing an opening into said chamber at the end of the rod bearing said piston, and an intake check valve mounted in the latter opening means of said piston rod, whereby an amount of liquid to be discharged can be drawn into said chamber through said channel of said piston rod and said intake check valve during rearward movement of said piston.
 2. The improvement as described in claim 1, further comprising abutting means on said piston rod and stopping means connected to the wall of said casing, said abutting means and stopping means being so disposed relative to each other in said casing that the movement of the piston in one of its two directions is arrested by said abutting means abutting against said stopping means.
 3. The improvement described in claim 2, wherein said stopping means for the movement of said piston comprise a stopping disk serving as an arresting member.
 4. The improvement described in claim 3, wherein the said stopping means is mounted on a lateral inner wall portion of the gun casing approximately at a level with the said piston rod in a zone away from a rearmost position of said piston.
 5. The improvement as described in claim 3, wherein said dosing device comprises, besides the said stopping disk, a setting knob which indicates the position of the said stopping disk, said knob being mounted on the outside of the gun casing wall, and being detachably joined with the stopping disk through an opening in the casing wall, and being adapted when rotated to carry the stopping disk along with it, whereby when detaching the knob of the stopping disk, the entire dosing device can be replaced.
 6. The improvement as described in Claim 2, wherein said abutting means is located at an end of said trigger lever.
 7. The improvement as described in claim 5, wherein said dosing means comprise a stop ring rigidly mounted on said piston rod and wherein said arresting member is a projection mounted on said stopping disk along a chord thereof, and said stop ring is provided with a recess whereby the forward discharge stroke of the piston is limited, depending upon the position of said stopping disk and arresting member thereon, either by the impact of said stop ring, or of one end of said trigger lever against said trigger lever against said projection.
 8. A dosing device for use in a squirting gun comprising a piston mounted on a reciprocable piston rod, which piston during its intake stroke is adapted for drawing liquid to be squirted from said gun in predetermined doses into a chamber provided therefor in a casing of said gun, said gun further having discharge means including a mouthpiece with an outlet check valve therein, a trigger lever for effecting the discharging movement of the piston and spring means for effecting the movement of said piston, by action transmitted via said trigger lever to said piston rod, which dosing device comprises adjustable stopping means and abutting means mounted on said piston rod for movement therewith, said stopping means being mounted on an inner, lateral wall of said gun casing approximately at a level with said piston rod in a zone adjacent an end position of said abutting means.
 9. A dosing device as described in claim 8, wherein said stopping means comprise a stopping disk serving as arresting member.
 10. A dosing device described in claim 9, wherein said dosing device further comprises a setting knob which indicates the position of the stopping disk and which is mounted on an outside wall portion of the gun and detachably joined with said stopping disk so as to turn said disk in unison therewith, when rotated.
 11. A dosing device as described in claim 8, wherein said stopping means comprise a circular stopping disk and arresting strip projecting out of the circular face of said disk toward the piston rod along a chord on said disk.
 12. A dosing device as described in claim 8, wherein said abutting means comprises a stop ring rigidly mounted on said piston rod, and extending far enough in the direction of said stopping means so as to abut against the latter when the piston rod moves in one of the stroke-limiting positions of said stopping means.
 13. A dosing device as described in claim 11, wherein said abutting means comprise a stop ring rigidly mounted on said piston rod in one of plural angular positions, said ring being provided with a marginal recess and said ring extending in the direction of said stopping disk so that said ring contacts said arresting strip in only one of said angular positions thereof.
 14. A dosing device as described in claim 13 wherein sAid abutting means further comprises a fork arm connected to an end of said trigger lever whereby said arm movably employs said piston rod and movably engages said stopping disk, said arresting strip being movable so that alignment of the marginal recess in said stop ring with said arresting strip permits movement of the stop ring past the arresting strip with motion of the piston rod limited by impact of said fork arm against the arresting strip.
 15. The improvement described in claim 2, wherein said stopping means comprise a stopping disk bearing an arresting member.
 16. A dosing device as described in claim 8, wherein said stopping means comprise a stopping disk bearing an arresting member.
 17. Dosage-regulating device for use in a pistol for the administration of liquid in determined doses, comprising a pistol casing having an external setting knob thereon and means providing a chamber therewithin; a reciprocable piston adapted to draw in and expel said liquid doses from said chamber, said piston being mounted on a hollow piston rod having stopping means mounted thereon and which projects from an end of said casing and is connected rearwardly outside said casing to a liquid supply line; a discharge tube connected with a valve and mouthpiece; and a trigger lever, whereby the expelling stroke of the piston is effected by manual operation of the said trigger lever; while the intake stroke of the piston is effected by means of a spring member acting upon the trigger lever and via the said lever upon the piston rod connected to the latter and upon the piston; said device comprising means which limit the stroke of the piston to a length corresponding to a determined liquid volume of said chamber means, said stroke-limiting means being located rearward of said chamber and being adapted to engage at least one of said stop means connected to said piston rod, said stroke-limiting means comprising a stopping disk angularly adjustable solely by turning of said external setting knob provided, said stopping disk being arranged at the inner sidewall of said pistol casing at about the level of the piston rod in the region between the wall of the pistol casing enclosing the piston-rod and an end of the chamber.
 18. A dosing device as described in claim 17 wherein said stopping means comprise a circular stopping disk and an arresting strip projecting out of the circular face of said disk toward the piston rod along a chord on said disk.
 19. Dosage-regulating device as described in claim 18, wherein said stroke-limiting means comprise a stop ring rigidly mounted on said piston rod and extending far enough in the direction of said stopping disk so as to abut against the arresting strip, but not against the disk itself, thereby limiting reciprocable movement of said piston rod in one direction of motion when said arresting strip is in one of two possible stroke-limiting reciprocable positions parallel to the axis of said piston rod.
 20. Dosage-regulating device as described in claim 19, wherein said stroke-limiting means further comprise an arm provided at the upper end of trigger lever which is movably connected with the piston rod, and wherein said stop ring is provided with a marginal recess, whereby, when said arresting strip is in one of two possible positions parallel to the axis of the piston rod, the stop ring can move past the arresting strip and the stroke of piston is limited by said arm abutting against said arresting strip. 